Stephen F. Heinemann, a Salk Research Institute professor whose pioneering work on neurotransmitter receptors in the brain helped lay the groundwork for understanding brain diseases, died Aug. 6 of complications of kidney failure at Vibra Hospital in San Diego. He was 75.

A professor of neuroscience, Heinemann focused his research on the molecular mechanisms by which nerve cells communicate with each other at specialized connections known as “synapses.” Groundbreaking findings from his laboratory supported the idea that many diseases of the brain result from deficits in communication between nerve cells, and he was widely considered one of the world’s most accomplished neuroscientists.

“Steve was a giant of 20th-century neuroscience,” said William Brody, president of the institute. “His discoveries opened many avenues to better understand the function of the brain and for pursuing new therapies for neurological disorders.”

Heinemann, born in Boston on Feb. 11, 1939, received his first chemistry set from his uncle, Emil Julius Klaus Fuchs, a theoretical physicist who contributed to the development of the atom bomb as part of the Manhattan Project but later confessed to spying for the Soviet Union.

Heinemann earned a bachelor of science degree from the California Institute of Technology in 1962 and a Ph.D. in biochemistry from Harvard University in 1967. He completed postdoctoral studies at the Massachusetts Institute of Technology and Stanford University School of Medicine. In 1970, he was invited to join the Salk core faculty and was among its first neuroscientists. He established the institute’s Molecular Neurobiology Laboratory, which by the late 1980s was ranked number one of its kind in the world.

A key outgrowth from Heinemann's work was the finding that deficits in receptor activity receptors account for a variety of human psychiatric maladies, including schizophrenia, bipolar disorder and Alzheimer's and Parkinson's diseases. He often warned that an Alzheimer’s epidemic threatened to swamp the medical system and led investigations into the brain’s receptors for nicotine–the group of receptors activated by the nicotine in tobacco and that may be damaged in Alzheimer’s disease.

Heinemann held several patents and had earned several awards. He was a member of the National Academy of Sciences, the National Institute of Medicine and the American Academy of Arts and Sciences and was a former President of the Society for Neuroscience. He received the Bristol-Myers Squibb Distinguished Achievement in Neuroscience Research Award and the McKnight Award for Research. In 2010, he was awarded the Julius Axelrod Prize for exceptional achievements in neuropharmacology and exemplary efforts in mentoring young scientists.